Plastic light aluminum alloy and process oe producing same



I 7 No Drawing.

Patented Mar. 5, I929.

. nears rr as earner VICTOR NOAK HYBINETTE, 9F JACKSON, MICHIGAN, ASSIGIIGB'TO IIYBINETTE PAT- ENTS CORPORATION, OF JACKSON, MI HIGAII. I

PLASTIC LIGHT ALUIIEINUM ALLOY AND PROCESS OF PRODUCING SAME.

My invention relates'to further development of the process and product described in a now-pending U. S. patent application, Ser. No. 165,246, filed Feb, 1, 1927.

Said application described an alloy of about 95-97% aluminum, with small quan tities of nickel, chromium, tungsten, molybdenum, manganese, iron, and Zinc in variableproporticns, to which is added a limited amount of copper and magnesium, about 03-05% of each. The peculiar properties of this alloy are set forth in said application to be age-hardening at high temperature between fairly Wide limits. Different predetermined degrees of physical properties are to be obtained by adjusting composition and length of time and degree of temperature of aging.

The present application covers the results of further research of the properties of this type of alloy. p

I have foundthat this alloy may be Worked after quenching from about 900950 F. both before and after aging, and particularly by alternating periods of aging and Working, and thatfor best results it should be somewhat modified in composition.

By such Work rolling or forging the property of not hardening under Work is more and more developed until a nearly perfect plastic alloy is obtained. In this Way I have produced sheets with over 50,000 lbs. yield point, Which may be bent over flat and the bend hammered out to an edge Without sign of cracking. That such metal is valuable for rivets, .piston rods, etc., as Well as for spinning and forming, is evident.

I proceed with the production of this alloy very much as described in the above referred toapplication. For the highest degree of plasticity I reduce the hardening elements such as manganese, or eliminate them alto gether. Iron in the presence of nickel seems not to be at all detrimental. In fact, if no iron is present the alloy must contain more of the other heavy metals to produce the same strength. In practice it is almost impossible to produce such alloy Without about 0.5% iron. Silicon hardens the alloy and reduce plasticity. So does magnesium and copper. I can get along With as little as 0.10-0.15% magnesium if the copper is high. All raw materials contain silicon, and I must therefore select low silicon raw materal so as not manganese iron and zinc.

Application filed July 11, 1927. Serial No. 205,028.

to have over 0.5% silicon in my final product. /Vhen silicon is low I may use more magne sium. M preferred composition contains about 1.52% of a mixture of nickel with chromium and/or tungsten, molybdenum,

lVhere the nickel is predominating, I may use 1% nickel and 0.5% chromium, or 1% nickel and 01-02% each of all the other metals, or I may use about 2% nickel only.

The presence of the chromium group of metals is not all important in this case, because I obtain all necessary strength by aging and Working. For non-corroding or nontarnishing, it is important to leave them in. The main thing is that I have nickel and some other metal because of all heavy metals. nickel seems to be the least harmful when it comes to producing an alloy of high plasticity, but nickel alone will not give an ultimate strength of much over 10,000 lbs. Zinc up to 2% does not seem to have any harmful influence. ,lVith these heavy metals I intro duce the copper, magnesium and silicon above referred to, so that my standard alloy Will 0. Aluminum about 96-97.00

The compounding of the alloy is well understood by those conversant With the art, and is fully described in U. S. Patent #1,579,481of April 6, 1926. The main idea is that I cut down all hardening elements to a minimum.-

The alloy so produced is forged or rolled hot and cold in the usual Way With or without intermediate annealing. It is then heated to about 900-950 F. and quenched in water.

If this alloy is aged for 1224 hours at temperature below 300 F. and if it contains less than 0.50% copper and magnesium combined, and less than 0.20% of magnesium, a slight increase in elongation is the only change observed. At 310 F. the alloy containing 0.10% magnesium and 0.50% copper becomes more ductile, but the ultimate strength and yield point remain unchanged. It seems to require 0.25% of each to obtain a commercially valuable heat treatment, although for some purposes the increased elongation may be desirable.

The quenched standard alloy has about 16,000 lbs. yield and 26,000 lbs. ultimate strength With about 12-15% elongation. Aged at 310 F. for 24; hours it Will show about 35,000 lbs. yield point and 42,000 lbs. ultimate strength, with 68% elongation. It Will notbend over Without cracking.

If it is rolled to a reduction of 20-30% in thickness after quenching, or if it is rolled the. same Way after aging, it gives about the same result of increased strength to about 48,000 lbs. yield point and ultimate elongation 23%, but a better bending quality. It is more plastic.

If it is rolled both before and after aging, and then rolled again and aged again, each rolling reduction being 2030%, and each period of aging lasting about l22 lhours at 300l00 F., it obtains the maximum of plas ticity, and strength above referred lo.

The final strength is a function of the total reduction after quenching and also, in a. lesser degree perhaps, of the composition of the alloy, but the degree of plasticity is depending mainly upon the number of steps of working and agin If the desired plasticity is not obtained, it is an indication that some of the additions have been made in too large quantity. I have rolled such finished product down from a thickness of 0.030 to 0.003, a reduction of 90% Without any sign of increased hardness.

sists in alloying the aluminum with quantities below the maximum used in an alloy designed for hardness and great strength, and by quenching and aging in combination With working, obtaining heretofore unheard-of qualities of plasticity and strength, which makes the product useful for certain purposes, Where lightness, low fatigue, strength, and non-corrodibility are needed.

I claim as my invention:

The process of producing a highly plastic, strong, lightaluminum alloy which comprises first alloying the aluminum With less than 2 5% of heavy metals and less than 70. of

copper, and of magnesium to make the resulting alloy only slightly responsive to heat treatment, and bringing out the strength and plasticity by Working the metal after it is quenched and before it is fully aged in inter niittent periods of aging and Working.

In testimony whereof I afiix my signature.

VICTOR NOAK HYBINEITE. 

